Evaluation of ethylene oxide, gamma radiation, dry heat and autoclave sterilization processes on extracellular matrix of biomaterial dental scaffolds

Tomographic evaluation of apexogenesis with human treated dentin matrix in young permanent molars: a split-mouth randomized controlled clinical trial

BACKGROUND

The concept of vital pulp therapy (VPT) of immature permanent teeth has evolved in recent years. There has been a great tendency towards investigating new pulp capping materials for perfect imitation for natural dentin-pulp complex formation process and restoring the normal tissue's characteristics. Therefore, this study aimed to assess the clinical and tomographic outcomes of apexogenesis with human treated dentin matrix (hTDM) compared to mineral trioxide aggregate (MTA).

MATERIALS AND METHODS

40 bilateral deep carious young mandibular first permanent molars (FPMs) in 20 healthy children aged between 6 and 8 years old were randomly allocated into 2 groups in which the FPMs treated with hTDM and MTA after pulpotomy procedure. The children were followed up clinically at 3, 6, 12, and 18 months. Tomographic evaluation was performed at baseline and 18-month evaluation period.

RESULTS

The overall clinical success rate was 100% in both groups. Regarding tomographic evaluation, the mean differences in root length, periapical diameter and area were statistically significant in each individual group but without statistically significant differences between both groups.

CONCLUSION

Human TDM hydrogel could be considered a promising pulpotomy agent for immature permanent teeth.

TRIAL REGISTRATION

The current clinical trial was recorded at clinicaltrials.gov, NCT06116695, 27/10/2023, Retrospectively registered.

Comparing the effect of using calcified autogenous nano dentin particles versus micro dentin particles in the healing of mandibular bony defects in New Zealand rabbits

OBJECTIVE

This study aimed to compare the regenerative effect of autogenous micro-dentin and nano-dentin particles on bone regeneration in rabbits' mandibular defects. Sixty adult New Zealand rabbits were randomly divided into three groups: a control group, a micro-dentin group, and a nano-dentin group. A critical-sized bony defect was created at the lower border of the mandible. Bone regeneration was evaluated at two, four, and eight weeks using light microscopy, cone beam computed tomography (CBCT) scans, and histomorphometric analysis.

RESULTS

Nano-dentin significantly enhanced bone density and defect closure, as evidenced by CBCT and histological analyses. At eight weeks, it promoted extensive new bone formation, nearly bridging the defect, with minimal residual graft material compared to the micro-dentin group. Histomorphometric analysis confirmed its superior osteogenic potential, demonstrating enhanced bone regeneration and graft resorption. These findings highlight nano-dentin as a highly effective biomaterial for mandibular bone repair.

Association of ethylene oxide exposure with serum neurofilament light chain levels among American adults

Objective

To explore the relationship between Ethylene oxide (EO) expousure and serum neurofilament light chain (NfL).

Method

A data of 559 adults from the 2013-2014 National Health and Nutrition Examination Survey (NHANES) was analyzed, and the relationship between log-transformed EO hemoglobin adducts (HbEO) and serum NfL levels was assessed using multiple linear regression models and restricted cubic spline functions. Stratified analysis was conducted to explore the correlations within different subgroups. Mediation analysis was employed to investigate potential mediating factors.

Results

The higher HbEO levels were consistently associated with elevated serum NfL concentrations among the study participants (β = 0.07, 95%CI: 0.00-0.14; p = 0.044), and serum NfL levels increased with rising HbEO levels (p for trend = 0.013). The restricted cubic spline results confirmed the linear relationship between serum NfL and HbEO. Subgroup analysis indicated a significant positive correlation, particularly among non-Hispanic white people, individuals aged 40-59, and heavy drinkers.

Conclusion

These findings highlighted the neurotoxic potential of EO and underscored the importance of monitoring EO exposure to mitigate its adverse health effects.

Decellularized tendon patch enhance biological and mechanical healing of large-to-massive rotator cuff tear in a rat chronic model: a comparison study of patch sterilization and storage methods

BACKGROUND

Large-to-massive rotator cuff tears (L-M RCTs) usually requires a patch to reconstruction. Decellularized tendon patch (DTP) was a biomimetic and effective material for reconstructing L-M RCTs. However, the protocol for DTP sterilization and storage is variable, which may influence their performance. The objective of this study is to optimize the protocol of DTP sterilization and storage and fabricate an off-the-shelf DTP with superior efficacy in enhancing the healing of L-M RCTs.

METHODS

DTPs were sterilized by ethylene oxide (EO) or gamma irradiation (GR), then preserved using cryo-preservation (CP) or freeze-drying (FD), thus preparing four kinds of DTPs (EO/CP-DTP, EO/FD-DTP, GR/CP-DTP, GR/FD-DTP). After evaluating their histology, microstructure, biomechanics, biocompatibility, and tenogenic inducibility in-vitro, a total of 88 male SD rats with chronic L-M RCTs were randomly divided into 4 groups, and then reconstructed with one of the four DTPs. At postoperative week 4 or 8, the supraspinatus tendon-to-humerus complexes were harvested for gross, micro-CT, histological, and mechanical evaluations.

RESULTS

In-vitro results indicated that the four kinds of DTPs showed excellent biocompatibility, and EO/CP-DTP showed an orderly collagen arrangement and higher tensile properties than the other DTPs. More importantly, the EO/CP-DTP can induce more interacted stem cells toward tenogenic lineages as compared with the other kinds of DTPs. Micro-CT showed that bony footprint in the four groups showed similar value in bone morphological parameters without significant difference. Histologically, the two CP-sterilized DTPs presented significantly higher scores than the FD-sterilized DTPs, while the EO/CP-DTP group exhibited slightly higher scores compared to the GR/CP-DTP group. As for the mechanical strength of the supraspinatus tendon-to-humerus complexes, a significantly higher failure load showed in the CP-sterilized DTPs when compared with the FD-sterilized DTPs at postoperative week 4 or 8.

CONCLUSION

DTP should be sterilized by EO and preserved using CP, owing that this type of DTP well preserved the intrinsic bioactivity and mechanical properties as well as showed superior efficacy in enhancing the healing of L-M RCTs.

LEVEL OF EVIDENCE

Basic Science Research; Animal Model.

Sterilization and Disinfection: Ensuring Infection Control in Dental Practices

Effective sterilization and disinfection are critical for infection control in dental practices, reducing healthcare-associated infections and ensuring patient safety. This review explores the principles, applications, and limitations of various sterilization and disinfection methods used in dentistry, including heat sterilization (steam and dry heat), chemical sterilization (ethylene oxide, hydrogen peroxide), and radiation methods (ultraviolet (UV) and gamma rays). Emphasis is placed on the effectiveness of each method against a range of pathogens, their suitability for different dental instruments, and advancements in technology such as vaporized hydrogen peroxide systems and antimicrobial coatings. Autoclave sterilization remains a cornerstone due to its reliability, while methods like UV rays and ozone offer innovative, material-friendly alternatives. The importance of verifying sterilization efficacy through biological indicators and maintaining proper storage protocols to ensure sterility is also highlighted. By integrating traditional techniques with emerging technologies, dental practices can enhance infection control standards while adapting to modern challenges.

Guidance on the assessment of biocompatibility of biomaterials: Fundamentals and testing considerations

BACKGROUND

Assessing the biocompatibility of materials is crucial for ensuring the safety and well-being of patients by preventing undesirable, toxic, immune, or allergic reactions, and ensuring that materials remain functional over time without triggering adverse reactions. To ensure a comprehensive assessment, planning tests that carefully consider the intended application and potential exposure scenarios for selecting relevant assays, cell types, and testing parameters is essential. Moreover, characterizing the composition and properties of biomaterials allows for a more accurate understanding of test outcomes and the identification of factors contributing to cytotoxicity. Precise reporting of methodology and results facilitates research reproducibility and understanding of the findings by the scientific community, regulatory agencies, healthcare providers, and the general public.

AIMS

This article aims to provide an overview of the key concepts associated with evaluating the biocompatibility of biomaterials while also offering practical guidance on cellular principles, testing methodologies, and biological assays that can support in the planning, execution, and reporting of biocompatibility testing.

Adverse effects of sterilization processes on the fundamental topographic properties of modified dental implant surfaces

The employ of sterilization processes are essential to investigate biomaterials aiming for experimental, preclinical, or clinical applications with biological tissues. However, responsive surface properties of biomaterials may be susceptible to sterilization processes, compromising important physio-chemical characteristics. For that reason, this in vitro study aimed to investigate the effects of three different processes for sterilization (humid heat under pressure, UVC-light exposure, and Gamma irradiation) on the major topographical properties of implant surfaces applied to dental bone-anchored implants and/or implant-abutments. Three groups of implant surfaces were developed: a smooth machined surface, a micro-texturized surface, and a hydrophilic micro-texturized surface. The implants were sterilized with three methodologies and characterized regarding surface morphology, elemental surface composition, roughness parameters, wettability characteristics, and compared to the samples as-developed. Surface morphology and roughness parameters were not modified by any of the sterilization processes applied. On the other hand, hydrophilic implants were negatively affected by autoclaving. After package opening, hydrophilic features showed to be sensible to atmospheric air exposition independently of the sterilization process performed. Our findings revealed significant chemical changes on the implant surfaces caused by autoclaving and UVC exposure; additionally, the results showed the importance of selecting an appropriate sterilization method when investigating hydrophilic implants so as not to generate imprecise outcomes.

The Impacts of the Sterilization Method and the Electrospinning Conditions of Nanofibrous Biodegradable Layers on Their Degradation and Hemocompatibility Behavior

The use of electrospun polymeric biodegradable materials for medical applications is becoming increasingly widespread. One of the most important parameters regarding the functionality of nanofiber scaffolds during implantation and the subsequent regeneration of damaged tissues concerns their stability and degradation behavior, both of which are influenced by a wide range of factors (the properties of the polymer and the polymer solution, the technological processing approach, the sterilization method, etc.). This study monitored the degradation of nanofibrous materials fabricated from degradable polyesters as a result of the sterilization method applied (ethylene oxide and gamma irradiation) and the solvent system used to prepare the spun polymer solution. Aliphatic polyesters PCL and PLCL were chosen for this study and selected with respect to the applicability and handling in the surgical setting of these nanofibrous materials for vascular bandaging. The results revealed that the choice of solvent system exerts a significant impact on degradation during sterilization, especially at higher gamma irradiation values. The subsequent enzyme-catalyzed degradation of the materials following sterilization indicated that the choice of the sterilization method influenced the degradation behavior of the materials. Whereas wave-like degradation was evident concerning ethylene oxide sterilization, no such behavior was observed following gamma-irradiation sterilization. With concern for some of the tested materials, the results also indicated the potential for influencing the development of degradation within the bulk versus degradation from the surface of the material. Both the sterilization method and the choice of the spinning solvent system were found to impact degradation, which was observed to be most accelerated in the case of PLCL (L-lactide-co-caprolactone copolymer) electrospun from organic acids and subsequently sterilized using gamma irradiation. Since we planned to use these materials in cardiovascular applications, it was decided that their hemocompatibility would also be tested. The results of these tests revealed that changes in the structures of the materials initiated by sterilization may exert thrombogenic and anticoagulant impacts. Moreover, the microscopic analysis suggested that the solvent system used in the preparation of the materials potentially affects the behavior of erythrocytes; however, no indication of the occurrence of hemolysis was detected.

Successful reimplantation of extruded bone segment in lower limb open fractures: case report and literature review

Objective

The aim of this study is to summarize and demonstrate the different sterilization methods and surgical techniques for open fractures with impacted bone segments in the lower limbs.

Methods

A retrospective analysis was conducted on the clinical characteristics, treatment methods, and outcomes of a case involving a 10.5 cm extruded segment of the femur in a 9-year-old male with a right femoral comminuted fracture treated at our center. Additionally, a retrospective review and summary were conducted on all reported cases of open fractures with impacted bone segments in the lower limbs.

Results

Our center treated a 9-year and 11-month-old male child who presented with a Gustilo type IIIB open fracture of the femur along with a large segment of the femur being ejected as a result of a car accident. The child was resuscitated to correct hypovolemic shock, underwent emergency wound debridement, and had Ilizarov external fixation of the femur. The ejected femur segment was sterilized using ethylene oxide and re-implanted four days after the injury. A literature review showed that out of the cases of open fractures with impacted bone segments in the lower limbs, there were 14 cases involving the femur and 5 cases involving the tibia. Among them, sterilization was performed using povidone-iodine in 6 cases, high-pressure steam sterilization in 3 cases, and other methods including gamma-ray irradiation and soaking in antibacterial solution were used in the remaining cases. In terms of surgical methods, 7 cases were fixed with locking plates, 3 cases were fixed with external fixation devices, 1 case was immobilized in a cast, 1 case was fixed with an intramedullary rod, and 4 cases involved a combination of external fixation and internal fixation. The average time for re-implantation was 7.6 days after the injury. There were no serious complications such as infection or non-union observed in any of the cases during follow-up.

Conclusion

Ethylene oxide can be considered a reliable choice for the reimplantation of displaced bone segments in open fractures after sterilization.

Decellularized extracellular matrix for organoid and engineered organ culture

The repair and regeneration of tissues and organs using engineered biomaterials has attracted great interest in tissue engineering and regenerative medicine. Recent advances in organoids and engineered organs technologies have enabled scientists to generate 3D tissue that recapitulate the structural and functional characteristics of native organs, opening up new avenues in regenerative medicine. The matrix is one of the most important aspects for improving organoids and engineered organs construction. However, the clinical application of these techniques remained a big challenge because current commercial matrix does not represent the complexity of native microenvironment, thereby limiting the optimal regenerative capacity. Decellularized extracellular matrix (dECM) is expected to maintain key native matrix biomolecules and is believed to hold enormous potential for regenerative medicine applications. Thus, it is worth investigating whether the dECM can be used as matrix for improving organoid and engineered organs construction. In this review, the characteristics of dECM and its preparation method were summarized. In addition, the present review highlights the applications of dECM in the fabrication of organoids and engineered organs.

Polysaccharide-bioceramic composites for bone tissue engineering: A review

Limitations associated with conventional bone substitutes such as autografts, increasing demand for bone grafts, and growing elderly population worldwide necessitate development of unique materials as bone graft substitutes. Bone tissue engineering (BTE) would ensure therapy advancement, efficiency, and cost-effective treatment modalities of bone defects. One way of engineering bone tissue scaffolds by mimicking natural bone tissue composed of organic and inorganic phases is to utilize polysaccharide-bioceramic hybrid composites. Polysaccharides are abundant in nature, and present in human body. Biominerals, like hydroxyapatite are present in natural bone and some of them possess osteoconductive and osteoinductive properties. Ion doped bioceramics could substitute protein-based biosignal molecules to achieve osteogenesis, vasculogenesis, angiogenesis, and stress shielding. This review is a systemic summary on properties, advantages, and limitations of polysaccharide-bioceramic/ion doped bioceramic composites along with their recent advancements in BTE.

Immunogenicity of decellularized extracellular matrix scaffolds: a bottleneck in tissue engineering and regenerative medicine

Tissue-engineered decellularized extracellular matrix (ECM) scaffolds hold great potential to address the donor shortage as well as immunologic rejection attributed to cells in conventional tissue/organ transplantation. Decellularization, as the key process in manufacturing ECM scaffolds, removes immunogen cell materials and significantly alleviates the immunogenicity and biocompatibility of derived scaffolds. However, the application of these bioscaffolds still confronts major immunologic challenges. This review discusses the interplay between damage-associated molecular patterns (DAMPs) and antigens as the main inducers of innate and adaptive immunity to aid in manufacturing biocompatible grafts with desirable immunogenicity. It also appraises the impact of various decellularization methodologies (i.e., apoptosis-assisted techniques) on provoking immune responses that participate in rejecting allogenic and xenogeneic decellularized scaffolds. In addition, the key research findings regarding the contribution of ECM alterations, cytotoxicity issues, graft sourcing, and implantation site to the immunogenicity of decellularized tissues/organs are comprehensively considered. Finally, it discusses practical solutions to overcome immunogenicity, including antigen masking by crosslinking, sterilization optimization, and antigen removal techniques such as selective antigen removal and sequential antigen solubilization.

Recent Advances in Cellulose-Based Hydrogels: Food Applications

In the past couple of years, cellulose has attracted a significant amount of attention and research interest due to the fact that it is the most abundant and renewable source of hydrogels. With increasing environmental issues and an emerging demand, researchers around the world are focusing on naturally produced hydrogels in particular due to their biocompatibility, biodegradability, and abundance. Hydrogels are three-dimensional (3D) networks created by chemically or physically crosslinking linear (or branching) hydrophilic polymer molecules. Hydrogels have a high capacity to absorb water and biological fluids. Although hydrogels have been widely used in food applications, the majority of them are not biodegradable. Because of their functional characteristics, cellulose-based hydrogels (CBHs) are currently utilized as an important factor for different aspects in the food industry. Cellulose-based hydrogels have been extensively studied in the fields of food packaging, functional food, food safety, and drug delivery due to their structural interchangeability and stimuli-responsive properties. This article addresses the sources of CBHs, types of cellulose, and preparation methods of the hydrogel as well as the most recent developments and uses of cellulose-based hydrogels in the food processing sector. In addition, information regarding the improvement of edible and functional CBHs was discussed, along with potential research opportunities and possibilities. Finally, CBHs could be effectively used in the industry of food processing for the aforementioned reasons.

Preparation and Use of Decellularized Extracellular Matrix for Tissue Engineering

The multidisciplinary fields of tissue engineering and regenerative medicine have the potential to revolutionize the practise of medicine through the abilities to repair, regenerate, or replace tissues and organs with functional engineered constructs. To this end, tissue engineering combines scaffolding materials with cells and biologically active molecules into constructs with the appropriate structures and properties for tissue/organ regeneration, where scaffolding materials and biomolecules are the keys to mimic the native extracellular matrix (ECM). For this, one emerging way is to decellularize the native ECM into the materials suitable for, directly or in combination with other materials, creating functional constructs. Over the past decade, decellularized ECM (or dECM) has greatly facilitated the advance of tissue engineering and regenerative medicine, while being challenged in many ways. This article reviews the recent development of dECM for tissue engineering and regenerative medicine, with a focus on the preparation of dECM along with its influence on cell culture, the modification of dECM for use as a scaffolding material, and the novel techniques and emerging trends in processing dECM into functional constructs. We highlight the success of dECM and constructs in the in vitro, in vivo, and clinical applications and further identify the key issues and challenges involved, along with a discussion of future research directions.